A typical warehouse environment is schematically shown in FIG. 1 and designated generally by the numeral 20. A loading dock 24 is disposed in front of the warehouse 20, and the loading dock 24 includes a plurality of bays 24d. Each bay 24d accommodates a flatbed trailer 23 that is backed up to the loading dock 24 in front of the warehouse 20, which is serviced by a forklift truck 21. As shown in FIG. 1 for example, some flatbed trailers 23 have a headboard 23c disposed at the end of the flatbed trailer 23 next to the cab 23a. Some flatbed trailers 23 have a set of wheels 23d beneath the end near the headboard 23c as well as at least one set of wheels 23d at the rear end of the flatbed trailer 23. A typical loading dock 24 will have several bays 24d so that several flatbed trailers 23 can be loaded and unloaded at the same time by several forklift trucks 21.
The back end of the loading dock 24 is an extension of the floor of a warehouse 20 that often has several vertically articulating overhead doors 20a controlling ingress and egress between the inside of the warehouse 20 and the loading dock 24. As shown in FIG. 1, the floor 24a of the loading dock 24 typically includes an overhang 24b, which typically is a metal plate that extends the floor 24a beyond the edge of the loading dock 24 and is disposed at a height that is just above the height of the flatbed trailer 23. The rear end of the flatbed trailer 23 can be slid beneath the overhang 24b when the rear end of the flatbed trailer 23 abuts against the rubber bumper 24c that often protects the forward free edge of the loading dock 24 beneath the overhang 24b. 
In the view of FIG. 1, parts of the loading dock 24 and overhang plate 24b have been cut away so that the viewer can see the rear end of the flatbed trailer 23 slid beneath the overhang 24b and abutting against the rubber bumper 24c at the forward free end of one of the bays 24d of the loading dock 24. Though not shown in FIG. 1, some loading docks 24 will have extensions of the loading dock 24 that project alongside and between two adjacent the loading bays 24d so that the forklift trucks 21 can be driven directly onto the sides of the flatbed trailers parked into such adjacent loading bays 24d. 
As shown in FIG. 1, many warehouse environments 20 rely on a forklift truck 21 for carrying and placing each pallet 22 onto a flatbed trailer 23 and removing each pallet 22 from the flatbed trailer 23. The truck cab 23a backs the attached flatbed trailer 23 into a loading bay 24d of a loading dock 24 at the warehouse 20. The forklift truck 21 drives out of the warehouse 20, across the floor 24a of the loading dock 24 and onto the flatbed trailer 23 to load or unload each pallet 22 containing cargo (not shown).
In addition to concentrating on placement of each pallet 22, the driver of the forklift truck 21 also must guard against losing track of the whereabouts of the side edges 23b of the flatbed trailer 23. The forklift operator must operate the forklift 21 so as to prevent any of the wheels 21a of the forklift truck 21 from driving past the side edge 23b of the flatbed trailer 23 and causing an accident that topples the forklift truck 21 and/or the pallet 22 and its cargo off the trailer 23.
For any such accident could injure the driver of the forklift truck 21, injure other workers in the area and/or damage the forklift truck 21 and the cargo on the pallet 22 being carried by the forklift truck 21 or in the vicinity of the forklift truck 21. Moreover, any fall protection apparatus for the forklift truck 21 must be sturdy enough to stop the forklift truck 21 from toppling over the side edges 23b of the flatbed trailer 23, forgiving enough so as to avoid damaging the forklift truck 21 in the process yet resilient enough to avoid suffering damage to itself from repeated impacts from the forklift truck 21. Additionally, any fall protection apparatus for the forklift truck 21 must not unduly interfere with the need for worker access to the flatbed trailer 23 so that workers are not inhibited from performing such tasks as installing tarps (not shown) over the cargo and removing same and strapping down the cargo and removing the straps (not shown) before unloading the cargo.